2002 V6. Difficult restarting when engine's hot.

2002 V6 175k miles. Bought new. Well maintained. Transmission recently replaced by Ford. Runs well when running. No engine check messages.

There is no cranking issue ... plenty of battery/starter oomph at all times! Starts and runs right away early in mornings when everything is cool. Cranks but does not run/restart after engine is hot ... several minutes must pass before successfully restarting.

This has been going on for some months now, but has worsened in hot weather. At first, beating on the IAC valve seemed to help ... but after replacing the IAC, we know we have greater issues. To date, we have done the following:

1. Replaced IAC control valve.

2. Replaced in-line Motorcraft fuel filter. We thought this was a winner because of the black gunk that spilled out of inlet end of filter ... no change!

3. Replaced fuel pump/sender. Used Ford PFS-399/YL8Z-9H307-AG. Heads up! Round tank seal and fuel line clips must be salvaged from old assembly .. are not included in new package! (Fuel in tank was surprisingly clean by the way.) ... no change.

4. Replaced ECT (Engine Coolant Temperature sensor). No change.

5. Replaced spark plugs. Cleaned/inspected coils. Original plugs were a bit worn ... but clean, looked pretty good. Coils were dirty, but no other faults ... so this was good, needed maint action.

So this is where we are ... all the above has made the vehicle run a bit better (perhaps) ... but the hot non-restart is still with us. And never a single code! Any ideas??

I had a SHO that after turning the engine off, it would get hotter under the hood and one of the control modules had a bad circuit board. When heated above a certain point it would warp and no longer make all the contacts. Since it didn't happen when running, no codes. I would take it out for a run to get it hot and come home, making sure it wouldn't start. Then take one of those little freezer packs and start cooling components that came to mind as a possible cause. I put a rag in between the two so that it wouldn't cool so fast that just the cooling might cause an issue. If it didn't start when that part was touchable with my hand, then on to the next. When I thought I had it after a start, I took it out for a run again, followed by a non-start, then cooling with a start.
Now you notice I was careful not to cool to quickly. You could possibly damage something using this method. I've seen guys use that bottled air for cooling and break the case on what they were using it on.
You could also take it to the dealer. They have some expensive computers to test things with. The ones around me want $200.00 for a hookup fee. And that might end up being cheap if you break a good part looking for a bad.
Just giving you options. My first thought when you described you problem was water in the spark plug tubes, but you later cancelled that idea.

Thanks for your post, 65comet ... You've added some possibilities. Seems you were pretty logical in your search.

So far we've been stabbing in the dark somewhat because we haven't yet anted up for a wiring diagram. Need to tend to that soon!

There was a chance to change out the EEC relay today during a "non-restart event". This had no impact!

Little update on (non) progress:

Finally were able to "listen" to injectors during a nonstart event. No injector clicking! This moves us to a different area ... The PCM, sensors, harnesses, etc, etc.

Since we could not find any easy means to thoroughly test sensors, we thought we would just throw some more money at the problem. Beware!, after much wasted time and effort, we have detemined that the cam and crank sensors for this vehicle are cataloged wrongly at AutoZone ... will not hook properly to the harness, with pigtail lengths as provided. However, found AdvanceAuto (a longer drive) to have exact replacements ... and lower cost!

Hopefully these sensors get installed today. (It looks as though the crank sensor has been upgraded ... now has a metal sleeve over the sensor probe ... for heat perhaps?)

Stay tuned ....

Well, its been a few days now ... no more failed starts ... and its running better than remembered.

The solution? ...the answer sems to have been the crankshaft position sensor! Time will tell ... but we THINK this is it! Strange that we never got a CEL!